These are books that appear on at least 2 of the extremely popular book list challenges on this site (see lists used below). BUT it only includes books I haven't read yet, thus forming a checklist for me. It still makes a decent list challenge and can be used to choose books to maximise your score on the "big challenges". Click on the link to use its companion challenge, which uses books I have read.
1-5: on 6 lists
6-10: 5 lists
11-20: 4 lists
21-44: 3 lists
45-122: 2 lists
Lists Used: 300 Books Everyone Should Read at Least Once; Amazon's 100 Books to Read in a Lifetime; 50 Books to Read Before You Die; BBC's Top 100 Books You Need to Read Before You Die; 99 Classic Books Challenge; 101 Best Selling Books of All Time; Books to Read to Be Considered Well Read; 200 Books Everyone Should Read.
The infamous & plagiaristic "BBC Believes You've Only Read 6 of These Books..." was NOT used.